I will start this off by pointing out there is a topic on this page called [size=3]All you need to know about DCC -for beginners[/size]
and it is very helpful in finding out how to go about working with DCC. If you can't find an answer there, then there are many people here who can help with specific subjects.
With regard to the Roco Advanced DCC system, it should be pointed out from the start that it is not a manufacturer that experienced DCC users would go to. Almost all the major model rail manufacturers have had a go at introducing their own DCC system, and almost without exception, they have stuffed it up. Probably the worst was Hornby, who managed to design a system that had more faults than good features.
The systems of choice are not ones made by model rail makers, but specialists in the field of DCC. And it is also probably true that the best control system may come from one manufacturer, while the decoder comes from another, and then certain DCC accessories come from yet another again.
Without starting an argument, the popular view is that NCE make the best control system, and probably TCS make the best decoders, while Loksound is very popular for sound equipped decoders. Some will disagree with this, but it is nevertheless a popular viewpoint.
As to fitting decoders to 50 year old models.. hmmm. I am also most likely in a similar age category to you, and have not had any difficulty adopting DCC, but I would be hesitant to do it with old models, as there are a number of pitfalls waiting.
Older models often had one terminal on the motor connected to the frame of the model, and therefore one side of the wheels, this is a killer situation for decoders, it will kill them stone dead in seconds. Both motor terminals must be isolated
from the frame and the wheels.
Also, those old motors consumed more power than modern motors and this higher current can often exceed the current capability of modern decoders. In addition, older motors with permanent magnets will suffer from loss of magnetism in the magnets fitted to the motor, and that in turn raises the current required to drive the motor.
A further issue is that unless you are skilled in electronics, fitting decoders to those old models will require a degree of knowledge that you may/may not possess, whereas newer models are generally designed to accept decoders already.
It may therefore be wise to consider buying more up-to-date models, rather than use your existing ones.